In this project the types of circulating antibody responses, genital secretion antibody responses and their interactions with other genital immune mechanisms will be studied and compared in order to develop a more thorough understanding of human immunity to gonorrhea. N. gonorrhoeae phenotypes of the colony types 1-4 and the opaque transparent colony variants will be studied. Both serum and genital secretion antibodies will be fractionated and the interactions of isolated immunoglobulins with intact gonococci and N. gonorrhoeae antigens will be examined. N. gonorrhoeae will be tested in bactericidal assays, and attachment and invasion studies of human mucosal epithelial cells and tissue explants. The role of antibodies from serum and secretions in blocking attachment or invasion will be characterized. The interactions of polymorphonuclear cells and both serum and genital secretion antibodies will be studied in opsonization assays. The immunoinhibitory role of seminal plasma and possibly other substances in semen or cervical secretions, will be studied to determine effects on N. gonorrhoeae and be of great importance in developing techniques for immunoprophylaxis of gonorrhea.